Indirectly lighted vertical scale indicator instrument

ABSTRACT

An indicator instrument has a transparent dial with horizontal indicia lines printed on the back side and with a masking plate covering the back side having vertical slots running past the indicia lines. Indicator tapes of translucent material at the back of the dial are moved vertically along the slots to indicate variations in variable quantities relative to the indicia lines. The dial is edge-lighted and the tapes are transilluminated by a lighting system including a light source and a plastic light diffuser plate.

limited States Patent [72] Inventors William W. Allen,.lr.

Plantation; Edward T. Lovasz, Fort Lauderdale, both 01 Fla. [21] Appl. No. 20,358 [22] Filed Mar. 17, 1970 [45] Patented Dec. 7, 1971 [73] Assignee McGraw-Edison Company Elgin, Ill.

[54] INDIRECTLY LIGHTED VERTICAL SCALE INDICATOR INSTRUMENT 8 Claims, 8 Drawing Figs.

[52] 11.8. C1 116/124, 116/135, 240/1 EL, 240/8.16, 340/316 [51] Int. Cl G091 9/00 [50] Field 01 Search 116/129, 124.4,129 E, 129 L, 129 N, 124; 40/130, 130 K, 152.2; 240/1 EL, 2.1, 8.16; 340/316 [56] References Cited UNITED STATES PATENTS 2,740,372 4/1956 Sturges 240/211 X Primary E.raminer Louis J Capozi Attorney-George H. Fritzinger ABSTRACT: An indicator instrument has a transparent dial with horizontal indicia lines printed on the back side and with a masking plate covering the back side having vertical slots running past the indicia lines. Indicator tapes of translucent material at the back of the dial are moved vertically along the slots to indicate variations in variable quantities relative to the indicia lines. The dial is edge-lighted and the tapes are transilluminated by a lighting system including a light source and a plastic light diffuser plate.

PATENTEDHEB mm 34625179 sum 1 0F 4 I N VI-iN ()RS 32 WILLIAM w. ALLEN.J 26 EDWARD T. LOVASZ 26 BY 10a 27 33 35 36 AGENT PATENTED DEC 71971 SHEET 2 [IF 4 q UTu I INVEN'IURS W'LLIAM W. ALL EN. JR.

EDWARD T. LOVASZ BY AGENT PATENTEUUEB 7I97l 34625179 sum 3 0F 4 33 fines I 30 Sb; 29b

-54 1 NVIiN'l (ms WILLI LEN. JR.

EDWA T. VASZ 2/ 26c AGENT llNDllRECTlLY LIGHTED VERTICAL SCALE INDICATOR INSTRUMENT An object of the invention is to provide a novel indicator instrument of the character mentioned which is characterized by a small depth, a wide viewing angle free of parallax and a freedom from stray light emission.

Another object is to provide such lighted indicator instrument which is adapted for any desired brightness and/or contrast between the vertical indicator tapes and the indirectly lighted dial.

Another object is to provide the instrument with a light source comprising a plurality of lamps on a unitary mounting which is insertable through an opening in the case without disturbing the instrument mechanism or its calibration.

These and other objects and features of the invention will be apparent from the following description and the appended claims.

In the description of our invention reference is had to the accompanying drawings, of which:

H0. 1 is a front perspective view of an indicator instrument according to the invention having four vertical indicator tapes for measuring four different variables;

FIG. 2 is a right side view of the front display portion of the instrument as seen with the case removed;

FIG. 3 is a fractional bottom view of the front display portion of the instrument with the case removed;

F IG. 4 is an enlarged horizontal sectional view taken on the line 4-4 of FIG. 1;

FIG. 5 is a fractional section on the line 55 of F IG. 4;

FIGS. 6 and 7 are partial sectional views respectively on the lines 6-6 of FIG. 5 and 7-7 of FIG. 6; and

H0. 8 is an exploded perspective view of the back lighting system and frame of the instrument.

By way of illustrative example the present instrument shown in the drawings is designed for clamp mounting in an aircraft instrument panel and is intended for flap-position indication to show the relative positioning of the inboard and outboard flaps of a modern jet transport plane.

The instrument has a glass dial plate 10 on the back side of which are printed as by an epoxy paint indicia comprising a series of horizontal index lines 11 and numerals 12. The back side of the dial plate is covered by a mask 13 as of aluminum film, say 0.0l0 or 0.0l5 thick, which has one or more vertical slots 14 of which four are shown by way of example. Two of these slots are in the left-half portion and the other two slots in the right-half portion of the dial. Preferably, the printed index lines are intersected by these vertical slots. Back of the slots 14 in contiguous relation to the mask 14 are respective indicator tapes 15 which traverse the dial plate throughout its height dimension. These tapes are trained around flanged rollers 16 at the top of the dial and around respective flanged rollers 17 at the bottom of the dial. The tapes are connected to respective servo motors 18 diagrammatically indicated. These servo motors are actuated according to the positioning of the respective flaps of the aircraft so that the tapes will show by the positioning of their indicator lines 15c relative to the index lines 11 the relative positioning of the flaps.

A feature of the invention is to transilluminate the tapes and to provide an indirect edge. lighting of the glass dial plate to permit easy reading of the instrument. For this purpose the tapes are made of a translucent material such for example as a teflon impregnated fiber glass. The lighting source is a series of light bulbs 19 mounted on a stick 20 for insertion through the case 21 of the instrument into a mounting position. In this mounting position the light bulbs are vertically spaced in a central slot 22s provided in a light diffuser plate 22. This diffuser plate is mounted in spaced parallel relation to the back side of the dial plate 10 and has a central vertically extending bar-shaped portion 220 from which extend two wedge-shaped side wings 22b and 22c. The diffuser plate is made of a light conducting plastic such as of Plexiglas or Lucite. The surfaces 23 of the side wings 22b and 220 confronting the dial plate 10 are parallel therewith and are painted white to diffuse light through the indicator tapes 15. The adjacent surface 24 of the central bar portion 22a is painted The outer (or back) surfaces 24 of the diffuser plate 22 arepolished as are also the end surfaces 26 so that they will have maximum light reflectibility. The end surfaces 26 are also beveled at 45 to the surfaces 23 so that the light conducted through the side wings to the end surfaces will be reflected therefrom towards the glass dial 10. The diffuser plate 22 has approximately the same width as the glass dial so that the reflected light emitted from the oppositeend surfaces will enter the opposite side border portions of the glass dial. For this purpose the mask 13 has a series of openings 27 near the side edges thereof to permit a transmission of light from the diffuser plate into the glass dial. Also, the side edges of the glass dial are beveled at 45 and the outer face of the border portions of the glass dial are covered by a mask 28 so that the light entering the border portions of the glass dial will be reflected through the dial plate in directions at right angles to the thickness dimension thereof. This reflected light from the edges is refracted within the dial plate to illuminate the indicia 1 l.

The border mask 28--which may be a thin strip of metal as of aluminum has a series of side tabs 28a (FIG. 4) bent around the edge of the dial back onto the mask 13 to hold the assembly together. Also, the border mask 28 has two tabs 28b at the top and two tabs 28c at the bottom which are bent back across the dial plate at right angles thereto. The pairs of tabs 28b and 286 are secured by screws 29 to trapezoidal-shaped mounting plates 29b and 290. The mounting plates are in turn secured by screws 30 to the end faces of the central barshaped portion 22a of the diffuser plate 22. ln this way the diffuser plate is held in a fixed spaced parallel relationship to the dial.

Applied against the front masking strip 28 is a cover glass 31. This cover glass is held in place by an end flange 32 of a surrounding cylindrical case member 33. This case member is secured by screws 34 (FIG. 4) to module frame members 35 of the instrument. A cup-shaped case 36 as of metal or plastic telescopes on the case member 33 in abutment with a locating rib 33a on the latter to complete the enclosure of the instrument.

The frame of the instrument includes a central frame bar 37 mounted midway between the module frame members 35, the frame bar 37 and frame members 35 being secured in fixed relation to each other by means not shown. Secured in spaced relation to opposite sides of the frame bar 37 are two intermodule frame members 39. These intermodule frame members are slotted to clear the side wings 22b and 22c of the diffuser plate, leaving arms 39d at the top and bottom of the instrument extending to the glass dial 10. These arms carry the inner ends of pivot rods 40 and 41 for the top and bottom guide rollers 16 and 17 around which the tapes 15 are trained. The forward portions of the outer module frame members 35 are curved inwardly and extended at 35a between each pair of guide rollers 16 and 17 at each side of the instrument to provide a second support for the pivot rods 40 and 41.

Secured by screws 42 to opposite sides of the end portion of the frame bar 37 are two rails 43 and 44. These rails extend beyond the end of the frame bar 37 and have confronting faces provided with rabbeted edges 44a and with vertical slots 45 to provide tongues 46 between the rabbeted edges and the slots. Slidably mounted between the rails in interlocking relation therewith is the mounting stick 20 having an aluminum strip 47 on its back side providing side flanges which slidably engage the slots 45. The mounting stick" has a trough 48 in its outer portion in 20 which are mounted the four light bulbs 19. The opposite sides of the trough portion 48 are faced with copper strips 49 to which are connected the terminals of the light bulbs 19. The faces of the rails confronting the trough portion 48 have two conductor springs 50 mounted thereon with extending connector terminals 51. The mounting stick" 20 can be slid through an opening 52 in the bottom of the case into its mounted position between the rails 43 and 44. When in this mounted position the bulbs 19 are disposed in the slots 22: of the diffuser plate 22. As the mounting stick" 20 nears its mounted position the conductor springs ride onto the copper strips 49 to complete electrical connection of the lead wires of the bulbs with the terminals 51. A slotted swivel screw 53 journaled on the outer end of the stick 20 and held thereto as by a retainer ring 54 is threaded into the opening 52 (FIG. to secure the mounting stick in place. Merely by unthreading the screw 53, as for example by a coin or screw driver, the stick can be withdrawn from the case to replace any light bulb which may have burned out. This removal of the light stick does not affect the assembly or the calibration of the instrument.

The edge-lighted dial and the transilluminated vertical indicating tapes of the present instrument provide a pleasing appearance when the instrument is lighted characterized by a balanced lighting over the entire display and by a brightness and/or contrast between the vertical indicating tapes and the dial portion of the display permitting easy readability free of parallax. Further, the design of the lighting system is such that the instrument can be dimmed to a very low light intensity as may be desired. A further feature is that the lighting system is virtually free of stray light emitted from the instrument that would be visible at any angle. Since the instrument is free of parallax and has a very small depth the instrument has a nearly 180 viewing angle.

The embodiment of our invention herein particularly shown and described is intended to be illustrative and not limitative of our invention since the same is subject to changes and modifications without departure from the scope of our invention, which we endeavor to express according to the following claims.

We claim:

1. A vertical scale instrument comprising a transparent dial having indicia on the back side thereof, an opaque mask covering the back side of said dial, said mask having a vertical slot running past said indicia, an indicator tape mounted for vertical movement along said slot for indicating variations in a variable quantity according to the positioning of said tape relative to said indicia, and a means for lighting said dial edgewise thereof whereby said indicia are illuminated by the light refracted within the dial.

2. The instrument set forth in claim 1 wherein said lighting means includes a light source and said tape is made of a translucent material for transillumination by said light source.

3. The instrument set forth in claim 2 including a light diffuser plate spanning said dial in spaced relation to the back side thereof, said diffuser plate having a mounting slot centrally thereof for said light source, said diffuser plate having beveled reflective end surfaces for reflecting light transmitted therethrough from said source to border portions of said dial free of said opaque mask, and said border portions of said dial having beveled reflective surfaces for directing the light received by said border portions through said dial in directions transverse to its thickness dimension.

4. The instrument set forth in claim 3 including an opaque strip covering the outer border surface of said dial to mask from view the light piped into the edges of said dial.

5. The instrument set forth in claim 3 wherein the back face of said diffuser plate has a polished reflective surface, and said diffuser plate is wedge-shaped from its center to opposite ends thereof for uniform distribution of light therethrough.

6. The instrument set forth in claim 5 wherein said indicia comprise scale lines extending transversely of said dial and said opaque mask has a vertical slot at each side of the central bar-shaped portion of said diffuser plate, including a vertical indicator tape along each of said slots between said mask and said diffuser plate, said diffuser plate having light transmitting surfaces facing said tapes and said tapes being made of translucent material to cause the same to be transilluminated from light received from said diffuser plate.

7. An indicator instrument comprising a transparent dial having indicia marks on the back side crosswise of the dial, an opaque mask covering the back side of the dial and having vertical slots in opposite side portions thereof extending past said indicia marks, vertically movable indicator tapes across said respective slots, said tapes being made of a translucent material, a diffuser plate in spaced parallel relation to the back side of said dial, a unitary elongate light source, a crosswise channel in said diffuser plate centrally thereof for receiving said elongate light source, said diffuser plate having a light transmitting surface confronting said tapes for transilluminating the same, and said diffuser plate and dial having border portions with reflective beveled end surfaces for causing light to be transmitted from the ends of the diffuser plate into the border portions of said dial and to be then reflected through the dial at right angles to its thickness dimension whereby said indicia are illuminated by refracted light within the dial.

8. The instrument set forth in claim 7 wherein said elongate light source comprises a bar-shaped mounting member having a series of light bulbs mounted thereon, said mounting member being slidable in said channel in interlocking relation with said difluser plate from one end of the diffuser plate, including a case for said instrument having an opening for receiving said mounting bar, and a screw journaled to one end of said mounting bar for removably securing said mounting bar in mounted position relative to said diffuser plate. 

1. A vertical scale instrument comprising a transparent dial having indicia on the back side thereof, an opaque mask covering the back side of said dial, said mask having a vertical slot running past said indicia, an indicator tape mounted for vertical movement along said slot for indicating variations in a variable quantity according to the positioning of said tape relative to said indicia, and a means for lighting said dial edgewise thereof whereby said indicia are illuminated by the light refracted within the dial.
 2. The instrument set forth in claim 1 wherein said lighting means includes a light source and said tape is made of a translucent material for transillumination by said light source.
 3. The instrument set forth in claim 2 including a light diffuser plate spanning said dial in spaced relation to the back side thereof, said diffuser plate having a mounting slot centrally thereof for said light source, said diffuser plate having beveled reflective end surfaces for reflecting light transmitted therethrough from said source to border portions of said dial free of said opaque mask, and said border portions of said dial having beveled reflective surfaces for directing the light received by said border portions through said dial in directions transverse to its thickness dimension.
 4. The instrument set forth in claim 3 including an opaque strip covering the outer border surface of said dial to mask from view the light piped into the edges of said dial.
 5. The instrument set forth in claim 3 wherein the back face of said diffuser plate has a polished reflective surface, and said diffuser plate is wedge-shaped from its center to opposite ends thereof for uniform distribution of light therethrough.
 6. The instrument set forth in claim 5 wherein said indicia comprise scale lines extending transversely of said dial and said opaque mask has a vertical slot at each side of the central bar-shaped portion of said diffuser plate, including a vertical indicator tape along each of said slots between said mask and said diffuser plate, said diffuser plate having light transmitting surfaces facing said tapes and said tapes being made of translucent material to cause the same to be transilluminated from light received from said diffuser plate.
 7. An indicator instrument comprising a transparent dial having indicia marks on the back side crosswise of the dial, an opaque mask covering the back side of the dial and having vertical slots in opposite side portions thereof extending past said indicia marks, vertically movable indicator tapes across said respective slots, said tapes being made of a translucent material, a diffuser plate in spaced parallel relation to the back side of said dial, a unitary elongate light source, a crosswise channel in said diffuser plate centrally thereof for receiving said elongate light source, said diffuser plate having a light transmitting surface confronting said tapes for transilluminating the same, and said diffuser plate and dial having border portions with reflective beveled end surfaces for causing light to be transmitted from the ends of the diffuser plate into the border portions of said dial and to be then reflected through the dial at right angles to its thickness dimension whereby said indicia are illuminated by refracted light within the dial.
 8. The instrument set forth in claim 7 wherein said elongate light source comprises a bar-shaped mounting member having a series of light bulbs mounted thereon, said mounting member being slidable in said channel in interlocking relation with said diffuser plate from one end of the diffuser plate, including a case for said instrument having an opening for receiving said mounting bar, and a screw journaled to one end of said mounting bar for removably securing said mounting bar in mounted position relative to said diffuser plate. 